JP6856707B2 - Three-phase transformer - Google Patents

Description

The present invention relates to a three-phase transformer.

So far, static induction electric appliances in which a plurality of windings are arranged in a straight line have been reported (for example, Patent Document 1). The static induction electric device described in Patent Document 1 has an N-phase N-leg main magnetic path (where N is 3 or more) and a main winding wound around each main leg, and is an intersection of N main legs. A control magnetic flux generating means for generating a control magnetic flux having a variable magnitude in a direction substantially orthogonal to any of the N-phase main magnetic fluxes is provided at the site, and the N-phase reactance is controlled by controlling the magnitude of the control magnetic flux by the generating means. Variable. The static induction electric device described in Patent Document 1 is a static induction electric device having a variable reactance, but the shape of the three-phase iron core is asymmetrical, and the lengths of the magnetic paths of the three phases are structurally the same. There is a problem that various values such as magnetic flux density are not completely equalized. Since the three phases are unbalanced, it is considered that heat generation other than normal heat generation and leakage flux are generated, and the coupling coefficient is considered to be about 0.3. A general transformer has a similar iron core structure, and the leakage flux also becomes a source of noise. For example, in a large transformer, it is not only surrounded by a cover, but basically cannot be approached. People are prohibited from entering by enclosing fences and the like. Furthermore, transformers are now strongly required to improve efficiency due to the global environment, and for that purpose, it is required to reduce unnecessary leakage flux.

Further, a power converter in which a three-phase coil is arranged on the circumference has also been reported (for example, Patent Document 2). The power converter described in Patent Document 2 includes two opposing yoke iron cores, three magnetic leg iron cores in which a coil is wound and a gap adjusting means is provided, and three pieces in which the coil is not wound. The two opposing yoke cores are connected by three magnetic leg cores and three zero-phase magnetic leg cores, and the three magnetic leg cores are , The three zero-phase magnetic leg cores are arranged on the circumference at a predetermined angle with respect to the concentric axis of the yoke core, and are between the three magnetic leg cores with reference to the concentric axis of the yoke core. It is arranged on the circumference. Further, there are three zero-phase magnetic leg iron cores, and magnetic flux flows through the zero-phase magnetic leg iron core, and the flow of magnetic flux to other phases is reduced, so that the mutual inductance becomes low. Therefore, the structure is not suitable for the use of mutual inductance. Even in a general transformer, the structure is not suitable because the magnetic flux corresponding to the mutual inductance is used.

Further, in the power converter described in Patent Document 2, the iron core has a structure in which a thin plate is wound in a roll shape, and the magnetic flux easily flows in the roll shape. Therefore, in the iron core, the path through which the magnetic flux flows is not the shortest, and the mutual inductance and self-inductance tend to be small. In addition, there is a problem in manufacturing and assembly that it is not suitable for processing holes and taps in manufacturing. Therefore, for example, there is a problem that it is difficult to use an inductance adjusting mechanism (screw or the like). Further, there is a problem that it is difficult to prevent the magnetic flux generated from the coil from leaking to the outside. That is, it is highly desired that the transformer has a small magnetic resistance and does not leak magnetic flux, and various measures have been taken in the iron core such as the use of grain-oriented electrical steel sheets and the method of assembling the iron core.

Japanese Unexamined Patent Publication No. 2016-048741 International Publication No. 2012/157053

An object of the present invention is to provide a highly efficient three-phase transformer in which the three phases are in equilibrium and the leakage flux is small.

The three-phase transformer according to the embodiment has a first plate shape between the first plate-shaped iron core and the second plate-shaped iron core arranged so as to face each other and the first plate-shaped iron core and the second plate-shaped iron core. A plurality of columnar iron cores that are multiples of 3 arranged so as to connect to the iron core or the second plate-shaped iron core, and at positions that are rotationally symmetric with respect to an axis equidistant from the central axes of the plurality of columnar iron cores. It has a plurality of columnar iron cores arranged and a coil including a plurality of primary coils and secondary coils that are multiples of 3 individually wound around the plurality of columnar iron cores.

According to the three-phase transformer according to the embodiment, a three-phase transformer in which the three phases are in equilibrium, the leakage flux is small, and the efficiency is high can be obtained.

It is a perspective view of the three-phase transformer which concerns on Example 1. FIG. It is a top view of the three-phase transformer which concerns on Example 1. FIG. It is a figure which shows the magnetic analysis result in the 1st plate-shaped iron core of the three-phase transformer which concerns on Example 1. FIG. It is a magnetic flux diagram of the iron core coil of the three-phase transformer which concerns on Example 1. FIG. It is a perspective view of the three-phase transformer which concerns on Example 2. FIG. It is a perspective view of the 2nd plate-shaped iron core of the three-phase transformer which concerns on Example 2, and the columnar iron core and the coil provided in the 2nd plate-shaped iron core. It is a perspective view after rotating the 1st plate-shaped iron core in the three-phase transformer which concerns on Example 2. FIG. In the three-phase transformer according to the second embodiment, it is an equivalent circuit of the three-phase transformer when the primary coil is combined with the secondary coil A. In the three-phase transformer according to the second embodiment, it is an equivalent circuit of the three-phase transformer when the primary coil is combined with the secondary coil B. It is a perspective view of the three-phase transformer which concerns on Example 3. FIG. It is a perspective view of the base material which constitutes the cover of the three-phase transformer which concerns on Example 3. FIG. It is a perspective view of the cover of the three-phase transformer which concerns on Example 3. FIG. It is sectional drawing of the three-phase transformer which concerns on Example 4. FIG. It is a perspective view of the three-phase transformer which concerns on Example 5. FIG. It is a side view of the three-phase transformer which concerns on Example 5. FIG. It is a perspective view of the 1st plate-shaped iron core which comprises the three-phase transformer which concerns on the modification of Example 5. FIG. It is a perspective view of the three-phase transformer which concerns on the modification of Example 5, and is the figure which shows the state which the inductance is large. It is a perspective view of the three-phase transformer which concerns on the modification of Example 5, and is the figure which shows the state which the inductance is small. It is a perspective view of the three-phase transformer which concerns on Example 7. FIG. It is a perspective view of the three-phase transformer which concerns on the modification of Example 7.

Hereinafter, the three-phase transformer according to the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to those embodiments and extends to the inventions described in the claims and their equivalents.

First, the three-phase transformer according to the first embodiment will be described. FIG. 1 shows a perspective view of the three-phase transformer according to the first embodiment. In the three-phase transformer 101 according to the first embodiment, the first plate-shaped iron core 1 and the second plate-shaped iron core 2, a plurality of columnar iron cores (31, 32, 33), and a plurality of primary coils (41a, 42a, It has a coil including 43a) and a plurality of secondary coils (41b, 42b, 43b). A three-phase transformer with the primary coil 41a and the secondary coil 41b as the U-phase coil, the primary coil 42a and the secondary coil 42b as the V-phase coil, and the primary coil 43a and the secondary coil 43b as the W-phase coil. Can be configured.

The first plate-shaped iron core 1 and the second plate-shaped iron core 2 are iron cores arranged so as to face each other. In the example shown in FIG. 1, the shapes of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 are disk-shaped, but the shape is not limited to such an example, and an elliptical disc-shaped or polygonal shape may be used. The first plate-shaped iron core 1 and the second plate-shaped iron core 2 are preferably composed of a magnetic material. The first plate-shaped iron core 1 and the second plate-shaped iron core 2 are provided with screw holes (1a, 1b, 1c, 2a (not shown), 2b, 2c) used for a gap adjusting mechanism described later.

The plurality of columnar cores (31, 32, 33) are connected between the first plate-shaped core 1 and the second plate-shaped core 2 with at least one of the first plate-shaped core 1 and the second plate-shaped core 2. It is a plurality of columnar iron cores arranged in multiples of 3. The plurality of columnar iron cores (31, 32, 33) are arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axes (31y, 32y, 33y) of the plurality of columnar iron cores.

The plurality of primary coils (41a, 42a, 43a) and secondary coils (41b, 42b, 43b) are coils that are multiples of 3 individually wound around the plurality of columnar iron cores (31, 32, 33). .. Assuming that the voltage of the primary coil is V ₁ , the number of turns is N ₁ , the voltage of the secondary coil is V ₂ , and the number of turns is N ₂ , the transformation ratio α is calculated by the following equation.
α = V ₁ / V ₂ = k × N ₁ / N ₂
However, k is the coupling coefficient of the primary coil and the secondary coil and is ideally 1.

In the example shown in FIG. 1, the number of columnar iron cores is set to 3, but the number is not limited to such an example. For example, six columnar iron cores may be arranged line-symmetrically and connected in series or in parallel to form one transformer, or six wirings may be provided as they are to form two transformers. Further, in the case of a single phase, the number of columnar iron cores may be two. The plurality of primary coils (41a, 42a, 43a) and the plurality of secondary coils (41b, 42b, 43b) are arranged so as to face each other at the ends of the first plate-shaped iron core 1 and the second plate-shaped iron core 2. It is preferably arranged more inside.

In the example shown in FIG. 1, the shape of the plurality of columnar iron cores (31, 32, 33) is cylindrical, but it may be elliptical or polygonal.

FIG. 2 shows a plan view of the three-phase transformer according to the first embodiment. FIG. 2 shows a plan view of the three-phase transformer shown in FIG. 1 as viewed from the first plate-shaped iron core 1 side. The plurality of columnar iron cores (31, 32, 33) are rotationally symmetric with the axes equidistant from the central axes (31y, 32y, 33y) of the plurality of columnar iron cores (31, 32, 33) as the rotation axis C _1. It is placed in position. As shown in FIG. 2, if the columnar iron core of the three columnar cores (31, 32, 33), each central axis (31y, 32y, 33y) to the rotation axis C ₁ at a position shifted by 120 degrees On the other hand, they are arranged so as to be rotationally symmetric. With such a configuration, the non-equilibrium state in the three phases can be eliminated. That is, when a load current is passed through a three-phase transformer, the magnetic flux of the primary coil and the magnetic flux of the secondary coil ideally cancel each other out, but if the three-phase transformer does not have a symmetrical shape, it may become unbalanced. Magnetic flux leakage occurs. By making the three-phase transformer symmetrical as in this embodiment, imbalance is eliminated, leakage flux is reduced, and efficiency is improved.

Further, the rotation shaft C ₁ may coincide with the central axis of the first plate-shaped iron core 1 or the second plate-shaped iron core 2.

FIG. 3 shows the results of magnetic analysis of the phase with three-phase alternating current in the first plate-shaped iron core of the three-phase transformer according to the first embodiment. The phase is such that the maximum current flows through the primary coil 41a wound around the columnar iron core 31, and half of the maximum current flows through the columnar iron cores 32 and 33 in opposite directions. Therefore, the magnetic flux goes from the columnar iron core 31 to the columnar iron cores 32 and 33. The magnetic flux density is high around the columnar iron core 31, and the magnetic flux density decreases as the distance from the columnar iron core 31 increases. The entire first plate-shaped iron core is widely used without waste, magnetic saturation is relaxed, and inductance does not easily decrease. Since a normal three-phase magnetic flux is generated in the columnar iron cores (31, 32, 33), the magnetic flux of one columnar iron core also passes through another columnar iron core, and not only self-inductance but also mutual inductance is positive. I am using it for. Therefore, the inductance is calculated by the following equation.
Inductance = self-inductance + mutual inductance As a result, the magnetic flux of mutual inductance can be effectively utilized.

Further, as shown in FIG. 3, the central portion of the first plate-shaped iron core 1 is also configured so that the magnetic flux passes through the central portion, so that the magnetic flux reaching the first plate-shaped iron core 1 from the columnar iron core 31 is linearly different from that of the other. It flows through the columnar iron cores (32, 33), and the efficiency with which the magnetic flux flows is good, leading to an improvement in mutual inductance.

FIG. 4 shows a magnetic flux diagram of the columnar iron core coil. FIG. 4 shows a magnetic flux line 61 generated from a columnar iron core 31 around which the primary coil 41a is wound. From FIG. 4, by arranging the first plate-shaped iron core 1 on the upper part of the primary coil (41a, 42a, 43a) and usually picking up the magnetic flux leaking from the upper part of the coil for any coil, not only the self-inductance but also the self-inductance It can be seen that this leads to an improvement in mutual inductance. The same applies to the second plate-shaped iron core 2 provided with the secondary coils (41b, 42b, 43b). Further, magnetic flux leakage can be blocked by a cover described later.

Further, from the magnetic analysis result of FIG. 3, the magnetic flux around the columnar iron cores (31, 32, 33) and the flow of the swelling magnetic flux between the columnar iron cores show that even if the columnar iron cores are two single phases, the first plate shape is formed. It can be seen that the mutual inductance can be increased through the iron core 1.

Further, as can be seen from FIG. 3, if the screw holes (1a, 1b, 1c) and tap holes used in the gap adjusting mechanism described later are provided at positions that do not affect the magnetic flux, the inductance will not be reduced.

Further, as can be seen from FIG. 3, when the first plate-shaped iron core 1 and the second plate-shaped iron core 2 are wound iron cores by laminating electromagnetic steel sheets in the axial direction of the columnar iron cores (31, 32, 33). It is possible to make the configuration in which the magnetic flux easily flows as compared with the above.

As a method for connecting the first plate-shaped iron core 1 and the second plate-shaped iron core 2 to the columnar iron core (31, 32, 33), the following method can be considered in the structure of the present invention.
(1) A recess is provided in the first plate-shaped iron core 1 or the second plate-shaped iron core 2 to insert a columnar iron core. (2) A screw hole is provided in the columnar iron core, and the first plate-shaped iron core 1 or the second plate-shaped iron core is provided. Screwing to provide a through hole in 2 (3) A method of providing a hole in the first plate-shaped iron core 1 or the second plate-shaped iron core 2 and the columnar iron core and press-fitting a pin, etc. For example, the first plate-shaped iron core 1 and the second plate A hole for fitting the columnar iron core (31, 32, 33) may be provided in the shaped iron core 2, and the columnar iron core (31, 32, 33) may be fitted into this hole. However, in consideration of the size of the transformer depending on the application, it may be combined by another method. For example, the first plate-shaped iron core 1 and the second plate-shaped iron core 2 may be fixed with screws.

In the above description, the configuration in which the first plate-shaped iron core 1 and the second plate-shaped iron core 2 are not provided with holes has been described, but at least one center of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 has been described. A hole may be provided in the portion.

Further, in the above description, the configuration in which the gap is not formed in the plurality of columnar iron cores (31, 32, 33) has been described, but at least one of the plurality of columnar iron cores (31, 32, 33) has been described. A first gap may be provided and an inductance may be generated by a gap due to air. Air has a relative magnetic permeability of 1, which is significantly different from the relative magnetic permeability of an iron core, and may be actively used to obtain a constant inductance. Here, the "first gap" refers to a gap formed in the opposite columnar iron core portions when the columnar iron core is separated into a plurality of columnar iron core portions. The first gap can be provided so as to face the plurality of columnar iron cores (31, 32, 33) in a plane orthogonal to the longitudinal direction. Further, in the first gap, the region around which the primary coils (41a, 42a, 43a) of the plurality of columnar iron cores (31, 32, 33) are wound and the secondary coils (41b, 42b, 43b) are wound. It is preferably provided between the turned regions. In addition, the reluctance is obtained by the length of the magnetic path / magnetic permeability / cross-sectional area, and the magnetic permeability of the columnar iron core is about 1000 times that of air. The air layer forming the gap is the main magnetic resistance, and the magnetic resistance of the iron core is negligible, while the latter is mainly the magnetic resistance of the iron core. Even if the air layer is provided in the gap in this way, the application will be different because the physical characteristics of the flow of magnetic flux will be greatly different due to the difference in magnetic permeability. In addition, the current when the iron core is saturated also differs greatly, and the application as a transformer differs depending on the presence or absence of a gap.

In a transformer, if there is even a slight situation where the magnetic fluxes do not cancel each other out, not only the transformation ratio but also electromagnetic waves, efficiency, etc. will be affected. It is required to be 0. According to the three-phase transformer according to the first embodiment, the magnetic resistance of the three phases can be made equal and small by the arrangement of the columnar iron cores and the shapes of the first plate-shaped iron core 1 and the second plate-shaped iron core 2, and the three-phase components can be obtained. At the same time, the total magnetic flux is 0 in the first plate-shaped iron core 1 and the second plate-shaped iron core 2 in which the magnetic flux runs in common. Further, when the exciting current flows through the primary coil, the magnetic flux flows through the columnar iron core, and the leakage flux can be reduced. In the iron core 2, the total magnetic flux is 0.

Next, the three-phase transformer according to the second embodiment will be described. FIG. 5 shows a perspective view of the three-phase transformer according to the second embodiment. FIG. 6 shows a perspective view of the second plate-shaped iron core of the three-phase transformer according to the second embodiment and the columnar iron core and the coil provided in the second plate-shaped iron core. The difference between the three-phase transformer 102 according to the second embodiment and the three-phase transformer 101 according to the first embodiment is that the primary coils (41a, 42a, 43a) are wound around each of the plurality of columnar iron cores. The first columnar core portion (31a, 32a, 33a) and the secondary coil A (41c, 42c, 43c) were wound into the second columnar core portion (31b, 32b, 33b) so as to be separable. The second plate-shaped iron core 2 has a plurality of third columnar core portions (34, 35, 36) and a plurality of turns having a different number of turns from the secondary coil A individually wound around the plurality of third columnar core portions. It has a secondary coil B (44, 45, 46), and the first plate-shaped iron core 1 or the second plate-shaped iron core 2 is configured to be rotatable about a rotation axis, and the primary coil (41a, 42a, The combination of the secondary coil A (41c, 42c, 43c) and the combination of the primary coil (41a, 42a, 43a) and the secondary coil B (44, 45, 46) can be selectively changed. It is a point that is configured to be. Since the other configurations of the three-phase transformer 102 according to the second embodiment are the same as the configurations of the three-phase transformer 101 according to the first embodiment, detailed description thereof will be omitted.

As shown in FIG. 5, the plurality of first columnar iron core portions (31a, 32a, 33a) around which the plurality of primary coils (41a, 42a, 43a) are wound are the plurality of secondary coils A (41c, 42c). , 43c) are wound so as to be separable from the plurality of second columnar iron core portions (31b, 32b, 33b). The plurality of first columnar iron core portions (31a, 32a, 33a) are fixed to the first plate-shaped iron core 1. On the other hand, as shown in FIG. 6, a plurality of second columnar core portions (31b, 32b, 33b) and a plurality of third columnar core portions (44, 45, 46) around which a plurality of secondary coils B (44, 45, 46) are wound ( 34, 35, 36) are fixed to the second plate-shaped iron core 2.

The plurality of first columnar iron core portions (31a, 32a, 33a) are arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axis of the plurality of first columnar iron core portions. In the examples shown in FIGS. 5 and 7, the plurality of first columnar iron core portions (31a, 32a, 33a) are rotationally symmetric with respect to the rotation axis at positions where their central axes are displaced by 120 degrees. Have been placed.

Similarly, the plurality of second columnar core portions (31b, 32b, 33b) are arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axis of the plurality of second columnar core portions. In the example shown in FIGS. 5 to 7, the plurality of second columnar iron core portions (31b, 32b, 33b) are rotationally symmetric with respect to the rotation axis at positions where their central axes are displaced by 120 degrees. Have been placed. Here, as shown in FIG. 5, when the first plate-shaped iron core 1 is arranged at a predetermined position, the plurality of first columnar iron core portions (31a, 32a, 33a) are formed by the plurality of second columnar iron core portions (31a, 32a, 33a). It is arranged so as to overlap with 31b, 32b, 33b).

Further, the plurality of third columnar iron core portions (34, 35, 36) are arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axis of the plurality of third columnar iron core portions. In the example shown in FIGS. 5 to 7, the plurality of third columnar iron core portions (34, 35, 36) are rotationally symmetric with respect to the rotation axis at positions where their central axes are displaced by 120 degrees. Have been placed. Here, as shown in FIG. 7, when the first plate-shaped iron core 1 is rotated and arranged at another predetermined position, the plurality of first columnar iron core portions (31a, 32a, 33a) have a plurality of first columnar iron core portions (31a, 32a, 33a). It is preferable that the three columnar iron core portions (34, 35, 36) are arranged so as to overlap with each other. For example, the plurality of third columnar core portions (34, 35, 36) are arranged at positions where the plurality of second columnar core portions (31b, 32b, 33b) are rotated by 60 degrees.

Since the plurality of first columnar core portions (31a, 32a, 33a) are configured to be separable from the plurality of second columnar core portions (31b, 32b, 33b), the first plate-shaped iron core 1 is the second. It can be rotated with respect to the plate-shaped iron core 2. Further, the first plate-shaped iron core 1 can be fixed to the cover 52 with screws or the like via screw holes (1a, 1b, 1c). The first plate-shaped iron core 1 can be fixed to the cover 52 with screws or the like at a new position after being rotated.

By rotating the first plate-shaped iron core 1 about the rotation axis, the combination of the primary coil (41a, 42a, 43a) and the secondary coil A (41c, 42c, 43c) and the primary coil ( The combination of 41a, 42a, 43a) and the secondary coil B (44, 45, 46) can be selectively changed, and the transformation ratio can be changed. In the example shown in FIG. 5, the primary coil (41a, 42a, 43a) is combined with the secondary coil A (41c, 42c, 43c). At this time, the iron core of the primary coil and the iron core of the secondary coil A are in contact with each other. Assuming that the voltage of the primary coil is V ₁ , the number of turns is N ₁ , the voltage of the secondary coil A is V ₂ , and the number of turns is N ₂ , the transformation ratio α is calculated by the following equation.
α = V ₁ / V ₂ = k × N ₁ / N ₂
However, k is the coupling coefficient of the primary coil and the secondary coil A and is ideally 1.

FIG. 7 shows a perspective view of the three-phase transformer according to the second embodiment after the first plate-shaped iron core 1 is rotated by 60 degrees in the direction opposite to the clock. In the example shown in FIG. 7, the primary coil (41a, 42a, 43a) is combined with the secondary coil B (44, 45, 46). Assuming that the voltage of the primary coil is V ₁ , the number of turns is N ₁ , the voltage of the secondary coil B is V ₃ , and the number of turns is N ₃ (≠ N ₂ ), the transformation ratio β is calculated by the following equation.
β = V ₁ / V ₃ = k'× N ₁ / N ₃
However, k'is the coupling coefficient of the primary coil and the secondary coil B and is ideally 1.

Assuming that the coupling coefficients k and k ′ are substantially equal, the turns N _{2 of the secondary coil A and the turns N 3} of the secondary coil B are different, so that the transformation ratios α and β have different values. Therefore, the transformation ratio can be switched to α or β by switching the coil to be combined with the primary coil between the secondary coil A and the secondary coil B.
When the primary coil and the secondary coil A are combined and the iron cores are in contact with each other, the two terminals of the secondary coil B are released. The iron core of the secondary coil B is in a state where it is not in contact with any iron core. The equivalent circuit of the three-phase transformer according to the second embodiment is shown in FIGS. 8A and 8B. FIG. 8A shows the equivalent circuit of a three-phase transformer when the primary coil is combined with the secondary coil A, and FIG. 8B shows the equivalent of the three-phase transformer when the primary coil is combined with the secondary coil B. It is a circuit. In FIGS. 8A and 8B, k = k ′ = 1. The contact and non-contact of the iron core creates a functioning iron core and a non-functioning iron core as a magnetic circuit, and the transformer is mechanically switched.

In the examples shown in FIGS. 5 and 7, a cover 52 is provided on the outer peripheral portion of the first plate-shaped iron core 1 and the second plate-shaped iron core 2, but even if the cover is not provided. The transformation ratio can be changed. When the cover 52 is not provided, the first plate-shaped iron core 1 and the second plate-shaped iron core 2 may be directly fixed by screws or the like.

In the above description, the configuration in which the transformation ratio is changed by rotating the first plate-shaped iron core 1 having three columnar iron cores has been described, but six or more columnar iron cores are described in the first plate-shaped iron core 1. May be placed. For example, a plurality of first columnar iron core portions B (not shown) in which a plurality of primary coils B are wound around a first plate-shaped iron core 1 are provided, and a plurality of primary coils B are provided as a plurality of secondary coils A or a plurality of. By combining with the secondary coil B of the above, the transformation ratio can be further changed in two ways (γ, δ), and can be changed in a total of four ways. Further, by connecting the wiring connected to each coil in series or in parallel, one transformer can be used, or two or more transformers can be used. Further, for example, the power supply voltage differs depending on each country, and it is necessary to change the transformation ratio as the electric device or electric machine to which the transformer is connected moves. By making it possible to change the transformation ratio, it is not necessary to newly prepare another transformer having a different transformation ratio, and it is possible to eliminate unnecessary transformers.

Next, the three-phase transformer according to the third embodiment will be described. FIG. 9 shows a perspective view of the three-phase transformer according to the third embodiment. The three-phase transformer 103 according to the third embodiment is different from the three-phase transformer 101 according to the first embodiment in that it is provided on the outer peripheral portions of the first plate-shaped iron core 1 and the second plate-shaped iron core 2. The point is that the columnar iron core (31, 32, 33), the plurality of primary coils (41a, 42a, 43a) and the cover 5 surrounding the plurality of secondary coils (41b, 42b, 43b) are further provided. Since the other configurations of the three-phase transformer 103 according to the third embodiment are the same as the configurations of the three-phase transformer 101 according to the first embodiment, detailed description thereof will be omitted.

When a transformer is provided with a gap in the columnar iron core, a large attractive force is generated in the axial direction of the columnar iron core at the gap portion. It is also said that even in a transformer without a gap, sound leads to noise due to the magnetostriction of the iron core. Magnetostriction is said to cause stress and deformation in the iron core due to changes in the magnetic flux in the iron core, leading to noise. Therefore, in order to structurally support this suction force, it is preferable to provide the cover 5. The material of the cover 5 may be iron, aluminum, or resin. Alternatively, the cover may be a magnetic material or a conductor.

FIG. 10A shows a perspective view of the base material constituting the cover of the three-phase transformer according to the third embodiment. It is preferable to use a ferromagnetic sheet for the base material 50. As the ferromagnetic sheet, for example, an electromagnetic steel sheet can be used. Further, it is preferable to apply an insulating treatment to the surface of the base material 50. Further, at least one of the first plate-shaped iron core 1, the second plate-shaped iron core 2, the plurality of columnar iron cores (31, 32, 33) and the cover 5 may be composed of a wound iron core.

FIG. 10B shows a perspective view of the cover of the three-phase transformer according to the third embodiment. By winding the rectangular base material 50 as shown in FIG. 10A along the outer peripheral portions of the first plate-shaped iron core 1 and the second plate-shaped iron core 2, the cylindrical cover 5 as shown in FIG. 10B is formed. Can be done. In the case of a transformer having a small diameter, the cylindrical cover 5 can be formed by winding the base material 50 around the tubular member. Further, as the cover, carbon steel or the like can be used in addition to the electromagnetic steel plate. In the case of a cylinder, since it is easy to process with a lathe, there is an advantage that it can be processed and manufactured at low cost and with high accuracy. Also, in the case of a cylinder, the volume inside the cylinder is maximized with the same outer circumference length, columnar iron cores, coils, etc. can be arranged to the maximum, the amount of members used can be reduced, and it is rational in terms of product life cycle. It is preferable in that it is a target.

The shape of the outer peripheral portion of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 is also preferably circular or elliptical. Like the cover 5, the first plate-shaped iron core 1 and the second plate-shaped iron core 2 can be processed and manufactured with high accuracy by having a simple shape such as a circle or an ellipse. Therefore, by combining the columnar iron cores (31, 32, 33) processed with high accuracy, the first plate-shaped iron core 1, the second plate-shaped iron core 2, and the cover 5, it becomes easy to manage the gap between the columnar iron cores. Since the size of the gap can be easily kept constant, the fluctuation of the gap length due to the suction force acting on the gap can be reduced. Even a transformer without a gap can be reduced by laminating or assembling laminated steel plates to have a small gap or an air layer, which has a magnetic resistance and a structure that can be processed with high accuracy. However, the cover 5 is not limited to a cylinder, and even if the shapes of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 are other than a circular or elliptical shape, this function can be exhibited.

By forming the cover 5 from iron, aluminum, or the like, it is possible to prevent magnetic flux and electromagnetic waves from leaking to the outside. By forming the cover 5 with a magnetic material such as iron, it also serves as a path for magnetic flux, and it is possible to prevent leakage flux from being emitted to the outside. That is, by manufacturing the cover 5 using a material having a high magnetic permeability such as iron, a path through which the magnetic flux from the columnar iron core passes through the first plate-shaped iron core 1, the cover 5, and the second plate-shaped iron core 2 is formed. Can be done. Further, by forming the cover 5 from iron, aluminum, or the like, it is possible to reduce the eddy current and improve the ease of passing the magnetic flux.

By forming the cover 5 with a material having a low magnetic permeability such as aluminum but a low resistivity, electromagnetic waves can be blocked. Generally, a three-phase alternating current is generated by a switching element such as an IGBT element, and a square wave electromagnetic wave may cause a problem in an EMC test or the like. Further, by forming the cover 5 with a resin or the like, it is possible to prevent the intrusion of liquids, foreign substances and the like.

Here, it is conceivable that the magnetic flux of direct current is superimposed on the three-phase alternating current for some reason. In the prior art, an example has been reported in which a magnetic leg iron core for zero phase is provided as a countermeasure against magnetic flux of direct current instead of zero phase, that is, three-phase alternating current. On the other hand, as shown in the magnetic analysis result of FIG. 3, the magnetic flux does not reach the cover 5 on the outer peripheral portion in this embodiment. However, when the cover 5 is made of a magnetic material and a direct current magnetic flux flows, it is conceivable that an unbalanced magnetic flux flows to the cover as well as the leakage flux. In such a case, it is possible to absorb the unbalanced magnetic flux with a cover made of a magnetic material so as not to have an adverse effect.

As shown in FIGS. 5 and 7, a cover 52 may be provided on the three-phase transformer according to the second embodiment. That is, a plurality of first columnar core portions (31a, 32a, 33a) and a plurality of second columnar core portions (31b, 32b, 33b) are provided on the outer peripheral portions of the first plate-shaped iron core 1 and the second plate-shaped iron core 2. ), A plurality of third columnar iron core portions (34, 35, 36), a plurality of primary coils (41a, 42a, 43a), a plurality of secondary coils A (41c, 42c, 43c) and a plurality of secondary coils B. It may further have a cover 52 surrounding (44, 45, 46). Further, a first plate-shaped iron core 1, a second plate-shaped iron core 2, a plurality of first columnar core portions (31a, 32a, 33a), a plurality of second columnar core portions (31b, 32b, 33b), and a plurality of third columns. At least one of the columnar core portions (34, 35, 36) and the cover 52 may be composed of a wound core. The cover 52 is preferably a magnetic material or a conductor. By providing the cover 52, it is possible to prevent electromagnetic waves from leaking from the primary coil, the secondary coil A, and the secondary coil B.

Next, the three-phase transformer according to the fourth embodiment will be described. FIG. 11 shows a cross-sectional view of the three-phase transformer according to the fourth embodiment. FIG. 11 shows a plane horizontal to the first plate-shaped iron core 1 at an arbitrary position in a plurality of columnar iron cores (31, 32, 33) around which a plurality of primary coils (41a, 42a, 43a) are wound in FIG. The cut sectional view is shown. The difference between the three-phase transformer 104 according to the fourth embodiment and the three-phase transformer 101 according to the first embodiment is that the central axes (31y, 32y, 33y) of the plurality of columnar iron cores (31, 32, 33) are present. It is a point that further has a rod-shaped body 6 arranged so as to have an axis (rotation axis C _{1) equidistant from the center axis.} Since the other configurations of the three-phase transformer 104 according to the fourth embodiment are the same as the configurations of the three-phase transformer 101 according to the first embodiment, detailed description thereof will be omitted.

The rod-shaped body 6 has a plurality of columnar iron cores (31, 32, 33) around which a plurality of primary coils (41a, 42a, 43a) are wound, and the shapes of the first plate-shaped iron core 1 and the second plate-shaped iron core 2. Therefore, it is preferable to arrange the plurality of columnar iron cores (31, 32, 33) so that the axis (rotation axis C _{1) equidistant from the central axis (31y, 32y, 33y) is the central axis.} The rod-shaped body 6 is preferably a magnetic material or a conductor.

Further, in the case of a transformer, when gaps are provided in a plurality of columnar iron cores (31, 32, 33), the suction force acting between the gaps is large, and the center of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 is located. By supporting it, the bending of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 can be effectively suppressed. Further, since the suction force works only in the direction in which the columnar iron cores facing each other in the gap are attracted to each other, the bending (and thus the fluctuation of the gap) can be effectively suppressed from the direction of the load.

In the example shown in FIG. 11, the three-phase transformer 104 is provided with the cover 5 and the rod-shaped body 6, but the rod-shaped body 6 may be provided without the cover 5. In this case, the first plate-shaped iron core 1 and the second plate-shaped iron core 2 may be directly fixed by screws or the like.

Further, in the three-phase transformer shown in FIG. 5, a rod-shaped body for fixing assistance (shown) having an axis equidistant from the central axes of the plurality of first columnar iron core portions (31a, 32a, 33a) as the central axis. It may be provided. The rod-shaped body is preferably a magnetic material or a conductor. By providing the rod-shaped body, stability can be improved when the first plate-shaped iron core 1 is rotated with respect to the second plate-shaped iron core 2.

In the three-phase transformer according to the above embodiment, at least one of the first plate-shaped iron core 1, the second plate-shaped iron core 2, the plurality of columnar iron cores (31, 32, 33), and the rod-shaped body 6 is wound. It may be composed of an iron core. Further, a rod-shaped central core may be arranged at the center of the wound core. By using the wound iron core, the exciting current and the iron loss can be reduced.

In the three-phase transformer shown in FIG. 5, the first plate-shaped iron core 1, the second plate-shaped iron core 2, a plurality of first columnar core portions (31a, 32a, 33a) and a plurality of second columnar core portions (31b, It is preferable that at least one of 32b, 33b) and a rod-shaped body (not shown) is composed of a wound iron core. Further, a rod-shaped central core may be arranged at the center of the wound core. By using the wound iron core, the exciting current and the iron loss can be reduced.

Next, the three-phase transformer according to the fifth embodiment will be described. FIG. 12 shows a perspective view of the three-phase transformer according to the fifth embodiment. FIG. 13 shows a side view of the three-phase transformer according to the fifth embodiment. The three-phase transformer 105 according to the fifth embodiment is different from the three-phase transformer 101 according to the first embodiment in that at least one of the first plate-shaped iron core 1 and the second plate-shaped iron core 2 and a plurality of columnar columns. A second gap is provided between the iron core (310, 320, 330) and at least one, and a gap adjusting mechanism (71, 72, 73) for adjusting the length d of the second gap is provided. .. Since the other configurations of the three-phase transformer 105 according to the fifth embodiment are the same as the configurations of the three-phase transformer 101 according to the first embodiment, detailed description thereof will be omitted.

As the gap adjusting mechanism (71, 72, 73), a screw provided on the first plate-shaped iron core 1 can be used. The tip surface of the screw comes into contact with the cover 5, and the first plate-shaped iron core 1 is also provided with a screw hole. By rotating the screw which is the gap adjusting mechanism (71, 72, 73), the first plate-shaped iron core 1 can be moved up and down. A second gap d can be formed between the first plate-shaped iron core 1 and the tips of a plurality of columnar iron cores (310, 320, 330), and the size of the second gap d can be adjusted by a screw. Here, the "second gap" refers to a gap formed between the first plate-shaped iron core 1 or the second plate-shaped iron core 2 and the tips of a plurality of columnar iron cores (310, 320, 330). By adjusting the size of the second gap d, the size of the inductance can be adjusted. In this way, it is possible to form inductances of different sizes with one transformer.

As described above, it is possible to fix the first plate-shaped iron core 1 only with the screws which are the gap adjusting mechanisms (71, 72, 73). However, due to the magnetic attraction acting on the second gap d, the cover 5 is threaded, the first plate-shaped iron core 1 is also provided with a threaded hole, and the first fixing screw (81, 82, 83) is provided. ), The first plate-shaped iron core 1 and the cover 5 may be fixed to strengthen the bond. On the other hand, the second plate-shaped iron core 2 and the cover 5 may be fixed with the second fixing screw (91, 92, 93) to strengthen the connection.

As the gap adjusting mechanism, instead of the screw, a member such as a spacer may be sandwiched between the first plate-shaped iron core 1 and the cover 5, and a gap may be formed by a fixing screw.

In the examples shown in FIGS. 12 and 13, an example in which the cover 5 is provided is shown, but when the cover 5 is not provided, the gap adjusting mechanism (71, 72, 73) is used up to the second plate-shaped iron core 2. The gap can be adjusted in the same manner as described above by passing the screw and the fixing screw (81, 82, 83).

FIG. 14 shows a perspective view of the first plate-shaped iron core 10 constituting the three-phase transformer according to the modified example of the fifth embodiment. As the gap adjusting mechanism, instead of screws, protrusions (11, 12, 13) as shown in FIG. 14 are provided on the surface of the first plate-shaped iron core 10 facing the columnar iron core (not shown). _{The protrusions (11, 12, 13) are provided along the position of a distance r from the center C 2} of the rotation of the first plate-shaped iron core 10, and are formed so that the length in the radial direction becomes shorter in the clockwise direction. Has been done. Further, the first plate-shaped iron core 10 is provided with a plurality of screw holes 14 in order to adjust the position in the circumferential direction. By rotating the first plate-shaped iron core 10, the contact area between the columnar iron core and the protruding portions (11, 12, 13) of the first plate-shaped iron core 10 is intentionally changed, and the magnitude of the inductance is adjusted. be able to.

FIG. 15 is a perspective view of the three-phase transformer 1051 according to the modified example of the fifth embodiment, showing a state in which the inductance is large. The protruding portions (11, 12, 13) are in contact with a plurality of columnar iron cores (310, 320, 330) at positions where the length in the radial direction is maximized. At this time, the inductance becomes maximum.

FIG. 16 is a perspective view of the three-phase transformer 1051 according to the modified example of the fifth embodiment, showing a state in which the inductance is small. The protrusions (11, 12, 13) are in contact with a plurality of columnar iron cores (310, 320, 330) at positions where the radial length is minimized. At this time, the inductance becomes the minimum.

In the configuration shown in FIGS. 15 and 16, when the inside of the three-phase transformer 1051 surrounded by the first plate-shaped iron core 10, the cover 5 and the second plate-shaped iron core 2 is to have a closed structure, a member is used. You may try to close the gap. By adopting a closed structure, it is possible to take measures against magnetic flux leakage, electromagnetic waves, dust and the like.

Next, the three-phase transformer according to the sixth embodiment will be described. The three-phase transformer according to the sixth embodiment is different from the three-phase transformer 103 according to the third embodiment in the portion surrounded by the first plate-shaped iron core 1, the second plate-shaped iron core 2, and the cover 5. The point is that it is filled with insulating oil or magnetic fluid. Since the other configurations of the three-phase transformer according to the sixth embodiment are the same as the configurations of the three-phase transformer 103 according to the third embodiment, detailed description thereof will be omitted.

As shown in FIG. 9, the portion surrounded by the first plate-shaped iron core 1, the second plate-shaped iron core 2 and the cover 5 is filled with insulating oil or magnetic fluid. For example, after the cover 5 is provided on the second plate-shaped iron core 2, it is filled with insulating oil or magnetic fluid, and the first plate-shaped iron core 1 is installed on the cover 5. In the case of a magnetic fluid, there is also an effect of being agitated by a magnetic field generated from a coil or the like inside the cover 5. The heat source is a plurality of primary coils (41a, 42a, 43a), a plurality of secondary coils (41b, 42b, 43b), and a plurality of columnar iron cores in which a plurality of primary coils and secondary coils are wound. 31, 32, 33), the insulating oil or magnetic fluid can convect and exchange heat with the outside by heat conduction to cool a plurality of primary coils, a secondary coil, and a plurality of columnar iron cores.

Next, the three-phase transformer according to the seventh embodiment will be described. FIG. 17 shows a perspective view of the three-phase transformer 106 according to the seventh embodiment. The difference between the three-phase transformer 106 according to the seventh embodiment and the three-phase transformer 103 according to the third embodiment is that the plurality of columnar iron cores (311, 321 and 331) have an air-core structure and an opening 311a. A point where insulating oil or magnetic fluid is circulated in a portion surrounded by the first plate-shaped iron core 1, the second plate-shaped iron core 2 and the cover 5 through the air core structure and the opening 311a. Since the other configurations of the three-phase transformer 106 according to the seventh embodiment are the same as the configurations of the three-phase transformer 103 according to the third embodiment, detailed description thereof will be omitted.

The plurality of columnar iron cores (311, 321, 331) penetrate the first plate-shaped iron core 1 and the second plate-shaped iron core 2, and the air core structure is that of the first plate-shaped iron core 1 and the second plate-shaped iron core 2. It is open to the outside. Therefore, the insulating oil or magnetic fluid can flow in from the first plate-shaped iron core 1 side through the air core structure and be discharged from the second plate-shaped iron core 2 side.

Further, cooling water or cooling oil may be allowed to flow through the air core structure of the plurality of columnar iron cores (311, 321, 331). With such a configuration, the cooling performance of the three-phase transformer 106 can be improved.

Further, the plurality of columnar iron cores (311, 321, 331) are provided with an air core structure and an opening 311a, and the first plate-shaped iron core 1, the second plate-shaped iron core 2 and the second plate-shaped iron core 2 are provided through the air core structure and the opening 311a. Insulating oil or magnetic fluid may be circulated in the portion surrounded by the cover 5. Further, efficiently, a plurality of primary coils (41a, 42a, 43a), a plurality of secondary coils (41b, 42b, 43b), and a plurality of columnar iron cores (a plurality of columnar iron cores in which a plurality of primary coils and secondary coils are wound) are wound. In order to cool 31, 32, 33), the heated insulating oil or magnetic fluid may be discharged to the outside of the three-phase transformer during circulation, cooled, and then returned. Although FIG. 17 shows an example in which one columnar iron core 311 is provided with an opening 311a, a plurality of openings may be provided in one columnar iron core, or one or a plurality of openings may be provided in a plurality of columnar iron cores. May be provided.

FIG. 18 shows a perspective view of a three-phase transformer according to a modified example of the seventh embodiment. Air cores in each of the plurality of first columnar core portions (310a, 320a, 330a), the plurality of second columnar core portions (310b, 320b, 330b), and the plurality of third columnar core portions (340, 350, 360). A structure may be provided, and an insulating oil or a magnetic fluid may be circulated in a portion surrounded by the first plate-shaped iron core 1, the second plate-shaped iron core 2 and the cover 5 through the air core structure.

Further, FIG. 17 also shows the wiring 100 of the coil wound around the plurality of columnar iron cores (311, 321 and 331). The connection portion 51 for taking out the wiring 100 to the outside of the three-phase transformer 106 is preferably provided at a position that does not affect the magnetic flux. In the case of a closed structure, airtightness can be maintained by using a connector, rubber packing, an adhesive or the like for the connecting portion 51. The connecting portion 51 may be provided at any position as long as it does not affect the magnetic flux, that is, the inductance.

1,10 1st plate-shaped core 11,12,13 Protruding part 2 2nd plate-shaped core 31,32,33 Columnar core 31a, 32a, 33a 1st columnar core 31b, 32b, 33b 2nd columnar core 34, 35, 36 Third columnar iron core portion 41a, 42a, 43a Primary coil 41b, 42b, 43b Secondary coil 41c, 42c, 43c Secondary coil A
44, 45, 46 Secondary coil B
5,52 Cover 6 Rod-shaped body 71,72,73 Gap adjustment mechanism

Claims (11)

The first plate-shaped iron core and the second plate-shaped iron core arranged so as to face each other,
A plurality of columnar cores in multiples of 3 arranged between the first plate-shaped core and the second plate-shaped core so as to be connected to the first plate-shaped core or the second plate-shaped core. A plurality of columnar iron cores arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axis of the plurality of columnar iron cores.
A coil containing a plurality of primary coils and a plurality of secondary coils that are multiples of 3 individually wound around the plurality of columnar iron cores.
A cover provided on the outer peripheral portion of the first plate-shaped iron core and the second plate-shaped iron core and surrounding the plurality of columnar iron cores, the plurality of primary coils, and the plurality of secondary coils.
Have,
Each of the plurality of columnar iron cores is formed by a plurality of columnar iron core portions in the longitudinal direction.
A first gap is formed between the plurality of columnar iron core portions.
Said first plate iron heart, the second gap is provided between at least one of the plurality of columnar core,
A gap adjusting mechanism for adjusting the length of the second gap is provided.
The gap adjusting mechanism includes a screw provided on the first plate-shaped iron core, and the tip surface of the screw is in contact with the cover.
A three-phase transformer in which the first plate-shaped iron core is moved by rotating the screw to adjust the second gap. The first plate-shaped iron core and the second plate-shaped iron core arranged so as to face each other,
A plurality of columnar cores in multiples of 3 arranged between the first plate-shaped core and the second plate-shaped core so as to be connected to the first plate-shaped core or the second plate-shaped core. A plurality of columnar iron cores arranged at positions that are rotationally symmetric with respect to an axis equidistant from the central axis of the plurality of columnar iron cores.
A coil containing a plurality of primary coils and a plurality of secondary coils that are multiples of 3 individually wound around the plurality of columnar iron cores.
A cover provided on the outer peripheral portion of the first plate-shaped iron core and the second plate-shaped iron core and surrounding the plurality of columnar iron cores, the plurality of primary coils, and the plurality of secondary coils.
Have,
Each of the plurality of columnar iron cores is formed by a plurality of columnar iron core portions in the longitudinal direction.
A first gap is formed between the plurality of columnar iron core portions .
In addition, an inductance adjustment mechanism is provided,
The inductance adjusting mechanism includes a plurality of protrusions provided on a surface of the first plate-shaped iron core facing the columnar iron core, and the plurality of protrusions are a predetermined distance from the rotation center of the first plate-shaped iron core. It is provided along the position of, and is formed so that the length in the radial direction becomes shorter in the clockwise direction, and a plurality of screws are provided on the first plate-shaped iron core to adjust the position in the circumferential direction. There is a hole,
A three-phase transformer in which the inductance is adjusted by changing the contact area between the columnar iron core and the protruding portion of the first plate-shaped iron core by rotating the first plate-shaped iron core. The three-phase transformer according to claim 1 or 2, wherein the plurality of primary coils and the plurality of secondary coils are arranged inside the ends of the first plate-shaped iron core and the second plate-shaped iron core. vessel. The three-phase transformer according to claim 1 or 2 , wherein the cover is a magnetic material or a conductor. The three-phase transformer according to claim 1 or 2 , wherein at least one of the first plate-shaped iron core, the second plate-shaped iron core, the plurality of columnar iron cores, and the cover is composed of a wound iron core. The three-phase transformer according to any one of claims 1 to 5 , further comprising a rod-shaped body for fixing assistance having an axis equidistant from the central axis of the plurality of columnar iron cores as the central axis. The three-phase transformer according to claim 6 , wherein the rod-shaped body is a magnetic material or a conductor. The three-phase transformer according to claim 6 or 7 , wherein at least one of the first plate-shaped iron core, the second plate-shaped iron core, the plurality of columnar iron cores, and the rod-shaped body is a wound iron core. The three-phase transformer according to claim 8 , wherein a rod-shaped central core is arranged at the center of the wound core. The three-phase transformer according to claim 1 or 2 , wherein the first plate-shaped iron core, the second plate-shaped iron core, and the portion surrounded by the cover are filled with an insulating oil or a magnetic fluid. The plurality of columnar iron cores have an air core structure and an opening, and insulating oil is formed in a portion surrounded by the first plate-shaped iron core, the second plate-shaped iron core, and the cover through the air core structure and the opening. Alternatively, the three-phase transformer according to claim 1 or 2 , which circulates a magnetic fluid.

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